/
open-feature-client.ts
308 lines (268 loc) · 9.14 KB
/
open-feature-client.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
import {
ClientMetadata,
ErrorCode,
EvaluationContext,
EvaluationDetails,
EventHandler,
FlagValue,
FlagValueType,
HookContext,
JsonValue,
Logger,
OpenFeatureError,
ProviderFatalError,
ProviderNotReadyError,
ResolutionDetails,
SafeLogger,
StandardResolutionReasons,
statusMatchesEvent
} from '@openfeature/core';
import { FlagEvaluationOptions } from '../evaluation';
import { ProviderEvents } from '../events';
import { InternalEventEmitter } from '../events/internal/internal-event-emitter';
import { Hook } from '../hooks';
import { OpenFeature } from '../open-feature';
import { Provider, ProviderStatus } from '../provider';
import { Client } from './client';
type OpenFeatureClientOptions = {
/**
* @deprecated Use `domain` instead.
*/
name?: string;
domain?: string;
version?: string;
};
export class OpenFeatureClient implements Client {
private _hooks: Hook[] = [];
private _clientLogger?: Logger;
constructor(
// functions are passed here to make sure that these values are always up to date,
// and so we don't have to make these public properties on the API class.
private readonly providerAccessor: () => Provider,
private readonly providerStatusAccessor: () => ProviderStatus,
private readonly emitterAccessor: () => InternalEventEmitter,
private readonly globalLogger: () => Logger,
private readonly options: OpenFeatureClientOptions,
) {}
get metadata(): ClientMetadata {
return {
// Use domain if name is not provided
name: this.options.domain ?? this.options.name,
domain: this.options.domain ?? this.options.name,
version: this.options.version,
providerMetadata: this.providerAccessor().metadata,
};
}
get providerStatus(): ProviderStatus {
return this.providerStatusAccessor();
}
addHandler(eventType: ProviderEvents, handler: EventHandler): void {
this.emitterAccessor().addHandler(eventType, handler);
const shouldRunNow = statusMatchesEvent(eventType, this.providerStatus);
if (shouldRunNow) {
// run immediately, we're in the matching state
try {
handler({
clientName: this.metadata.name,
domain: this.metadata.domain,
providerName: this._provider.metadata.name,
});
} catch (err) {
this._logger?.error('Error running event handler:', err);
}
}
}
removeHandler(notificationType: ProviderEvents, handler: EventHandler): void {
this.emitterAccessor().removeHandler(notificationType, handler);
}
getHandlers(eventType: ProviderEvents) {
return this.emitterAccessor().getHandlers(eventType);
}
setLogger(logger: Logger): this {
this._clientLogger = new SafeLogger(logger);
return this;
}
addHooks(...hooks: Hook[]): this {
this._hooks = [...this._hooks, ...hooks];
return this;
}
getHooks(): Hook[] {
return this._hooks;
}
clearHooks(): this {
this._hooks = [];
return this;
}
getBooleanValue(flagKey: string, defaultValue: boolean, options?: FlagEvaluationOptions): boolean {
return this.getBooleanDetails(flagKey, defaultValue, options).value;
}
getBooleanDetails(
flagKey: string,
defaultValue: boolean,
options?: FlagEvaluationOptions,
): EvaluationDetails<boolean> {
return this.evaluate<boolean>(flagKey, this._provider.resolveBooleanEvaluation, defaultValue, 'boolean', options);
}
getStringValue<T extends string = string>(flagKey: string, defaultValue: T, options?: FlagEvaluationOptions): T {
return this.getStringDetails<T>(flagKey, defaultValue, options).value;
}
getStringDetails<T extends string = string>(
flagKey: string,
defaultValue: T,
options?: FlagEvaluationOptions,
): EvaluationDetails<T> {
return this.evaluate<T>(
flagKey,
// this isolates providers from our restricted string generic argument.
this._provider.resolveStringEvaluation as () => EvaluationDetails<T>,
defaultValue,
'string',
options,
);
}
getNumberValue<T extends number = number>(flagKey: string, defaultValue: T, options?: FlagEvaluationOptions): T {
return this.getNumberDetails(flagKey, defaultValue, options).value;
}
getNumberDetails<T extends number = number>(
flagKey: string,
defaultValue: T,
options?: FlagEvaluationOptions,
): EvaluationDetails<T> {
return this.evaluate<T>(
flagKey,
// this isolates providers from our restricted number generic argument.
this._provider.resolveNumberEvaluation as () => EvaluationDetails<T>,
defaultValue,
'number',
options,
);
}
getObjectValue<T extends JsonValue = JsonValue>(
flagKey: string,
defaultValue: T,
options?: FlagEvaluationOptions,
): T {
return this.getObjectDetails(flagKey, defaultValue, options).value;
}
getObjectDetails<T extends JsonValue = JsonValue>(
flagKey: string,
defaultValue: T,
options?: FlagEvaluationOptions,
): EvaluationDetails<T> {
return this.evaluate<T>(flagKey, this._provider.resolveObjectEvaluation, defaultValue, 'object', options);
}
private evaluate<T extends FlagValue>(
flagKey: string,
resolver: (flagKey: string, defaultValue: T, context: EvaluationContext, logger: Logger) => ResolutionDetails<T>,
defaultValue: T,
flagType: FlagValueType,
options: FlagEvaluationOptions = {},
): EvaluationDetails<T> {
// merge global, client, and evaluation context
const allHooks = [
...OpenFeature.getHooks(),
...this.getHooks(),
...(options.hooks || []),
...(this._provider.hooks || []),
];
const allHooksReversed = [...allHooks].reverse();
const context = {
...OpenFeature.getContext(this?.options?.domain),
};
// this reference cannot change during the course of evaluation
// it may be used as a key in WeakMaps
const hookContext: Readonly<HookContext> = {
flagKey,
defaultValue,
flagValueType: flagType,
clientMetadata: this.metadata,
providerMetadata: this._provider.metadata,
context,
logger: this._logger,
};
try {
this.beforeHooks(allHooks, hookContext, options);
// short circuit evaluation entirely if provider is in a bad state
if (this.providerStatus === ProviderStatus.NOT_READY) {
throw new ProviderNotReadyError('provider has not yet initialized');
} else if (this.providerStatus === ProviderStatus.FATAL) {
throw new ProviderFatalError('provider is in an irrecoverable error state');
}
// run the referenced resolver, binding the provider.
const resolution = resolver.call(this._provider, flagKey, defaultValue, context, this._logger);
const evaluationDetails = {
...resolution,
flagMetadata: Object.freeze(resolution.flagMetadata ?? {}),
flagKey,
};
this.afterHooks(allHooksReversed, hookContext, evaluationDetails, options);
return evaluationDetails;
} catch (err: unknown) {
const errorMessage: string = (err as Error)?.message;
const errorCode: ErrorCode = (err as OpenFeatureError)?.code || ErrorCode.GENERAL;
this.errorHooks(allHooksReversed, hookContext, err, options);
return {
errorCode,
errorMessage,
value: defaultValue,
reason: StandardResolutionReasons.ERROR,
flagMetadata: Object.freeze({}),
flagKey,
};
} finally {
this.finallyHooks(allHooksReversed, hookContext, options);
}
}
private beforeHooks(hooks: Hook[], hookContext: HookContext, options: FlagEvaluationOptions) {
Object.freeze(hookContext);
Object.freeze(hookContext.context);
for (const hook of hooks) {
hook?.before?.(hookContext, Object.freeze(options.hookHints));
}
}
private afterHooks(
hooks: Hook[],
hookContext: HookContext,
evaluationDetails: EvaluationDetails<FlagValue>,
options: FlagEvaluationOptions,
) {
// run "after" hooks sequentially
for (const hook of hooks) {
hook?.after?.(hookContext, evaluationDetails, options.hookHints);
}
}
private errorHooks(hooks: Hook[], hookContext: HookContext, err: unknown, options: FlagEvaluationOptions) {
// run "error" hooks sequentially
for (const hook of hooks) {
try {
hook?.error?.(hookContext, err, options.hookHints);
} catch (err) {
this._logger.error(`Unhandled error during 'error' hook: ${err}`);
if (err instanceof Error) {
this._logger.error(err.stack);
}
this._logger.error((err as Error)?.stack);
}
}
}
private finallyHooks(hooks: Hook[], hookContext: HookContext, options: FlagEvaluationOptions) {
// run "finally" hooks sequentially
for (const hook of hooks) {
try {
hook?.finally?.(hookContext, options.hookHints);
} catch (err) {
this._logger.error(`Unhandled error during 'finally' hook: ${err}`);
if (err instanceof Error) {
this._logger.error(err.stack);
}
this._logger.error((err as Error)?.stack);
}
}
}
private get _provider(): Provider {
return this.providerAccessor();
}
private get _logger() {
return this._clientLogger || this.globalLogger();
}
}